Method and apparatus for use in the transportation of solids

ABSTRACT

A method and apparatus to increase the pressure of a mixture of liquid and solids in a pipeline for transportation of the mixture through the pipeline at a constant velocity. The mixture is pressurized in a series of chambers into which alternately flows low-pressure liquid and out of which alternately flows highpressure liquid. The low-pressure liquid is continuously diverted from the pipeline into the chambers while an equal amount of the high-pressure liquid is diverted from the chambers back into the pipeline.

nited States Patent [72] Inventor Maurice A. l-luso 5310 Las Lomas St.,Long Beach, Calif.

xxxwx 25515 999 9 333 3 ///2/ 77717 1.11. l 444 4 am 6 M S e mwmmm fu aCLVSW 04589 45555 99999 11111 43374 95589 52500 6332].. 97048 22222 0177 99 11 6 8 122 1 Sam 0 n. ,M 95J a d N w n Wm flm AFP 1]] 125 224 [[1Primary ExaminerRobert M. Walker Attorney-Lyon & Lyon [54] METHOD ANDAPPARATUS FOR USE IN THE ABSTRACT: A method and apparatus to increasethe pressure of a mixture of liquid and solids in a pipeline fortransportation of the mixture through the pipeline at a constantvelocity. The mixture is pressurized in a series of chambers s D n I L mFm 0F mm w m T8 m m m 8 wmu N-mC AC R S TmU H .F04b 17/00, into whichalternately flows low-pressure liquid and out of F041) 9/08, F04b 35/00which alternately flows high-pressure liquid. The low-pressure [50]Field of 417/53, 65, liquid is continuously diverted from the pipelineinto the 121, 122, 205, 206, 225, 339, 382, 389, 390, 395, chamberswhile an equal amount of the high-pressure liquid is diverted from thechambers back into the pipeline.

E 6 a NV em 5 W W e Z 0 mew ,e W 5 2 W U 7/ T P 2% HH m 5 WW alssaesgsPATENTEU M82819?! SHEET 2 [IF 2 mi i \ks g m ubkb xvi INVENTOR g zawsMAO/Z05 A H050 METHOD AND APPARATUS FOR USE IN THE TRANSPORTATION OFSOLIDS The invention relates to the transportation of solids and moreparticularly is concerned with the transportation of solids mixed with aliquid through a pipeline.

Long distance transportation of petroleum and petroleum products througha pipeline is well known and is both economical and convenient. Thepetroleum transportation system generally includes one or more pumpingstations interposed in the pipeline for raising the pressure of thepetroleum liquid to a high level. The stations generally employcentrifugal pumps because of their lower first cost, their adaptabilityto varying pumping rates, and their adaptability to multistation systemsbrought about by their nonpositive displacement and nonpulsingcharacteristics.

Similar transportation of solids, such as coal, iron ore, sulfur,limestone, and wood chips, suspended in a liquid medium has long beenconsidered as having attractive possibilities from the standpoint ofconvenience and reduced costs. Generally, the major obstacle whichconfronts long distance pipelining of solids is the development of aneconomical pump unit which will develop the high-pressure head requiredto transfer the slurry over long distances. The pump unit must also beadapted to raise the pressure head of the slurry while maintaining aconstant velocity of slurry flow in the pipeline.

Success in part has been achieved in transporting slurry in a pipelinethrough the use of reciprocating-type pumps. However, these pumps havevery high initial costs and high maintenance costs. Centrifugal pumps ofthe type used in petroleum pipelining are considered particularlydesirable and have been used in some instances on short pipelines wherethe pressures involved are relatively low. However, in long distancepipelining where high pressure and high volume is required centrifugalpumps have proved unsuccessful because the abrasive action of the slurrycauses damage to the pumps, creating considerable maintenance.

Therefore, the primary object of this invention is to provide a meansfor developing the pressure head necessary to transport slurry over longdistances through a pipeline. In accordance with this object it isimportant that the pressure head of the slurry be raised without varyingor reducing the velocity of the slurry flow in the pipeline.

A further object of this invention is to employ the use of centrifugalpumps without subjecting the pumps to the abrasive action of the slurrybeing pumped.

Another object of this invention is to transport solids over longdistances through a pipeline by economical and practical means.

To accomplish these objects, the invention includes a pumping unit, ofwhich there may be a plurality over the entire length of the pipeline,to raise the pressure level of the slurry being transported through thepipeline. The pumping unit includes a series of chambers, each up toseveral hundred feet in length. Each chamber is adapted to fill up withlow-pressure slurry and then empty high-pressure slurry. Means areprovided to continuously divert from the pipeline low-pressure slurryalternately into the chambers while continuously diverting alternatelyfrom the chambers high-pressure slurry back into the pipeline. Arecirculating liquid which has been pressurized by one or morecentrifugal pumps increases the pressure of the slurry in the chambersand means in the chambers are provided to maintain this liquid separatefrom the slurry. The filling and emptying of the slurry in the chambersis sequentially controlled in such a manner to provide continuous flowof slurry at all times into and out of the chambers and ensure that theamount of low-pressure slurry diverted continuously from the pipeline isequal to the amount of highpressure slurry being diverted continuouslyback into the pipeline.

Other and further objects of this invention will be made readilyapparent from the accompanying drawings and following detaileddescription.

IN THE DRAWINGS FIG. 1 is a schematic view illustrating the emptying andfilling of the chambers.

FIG. 2 is a schematic view illustrating the sequential operation of thevalves when three chambers are employed.

FIG. 3 is a schematic view illustrating an alternative embodiment of thechamber.

FIG. 4 is a schematic view illustrating a still further alternativeembodiment of the chamber.

Referring now in detail to the drawings, the pumping unit is generallydesignated 10. The pumping unit 10 as shown in FIG. 1 includes a seriesof three identical chambers 11, 12 and 13. From the following discussionit will be made evident that the invention in its preferred formincludes at least three chambers, but is not necessarily limited tothree chambers. However, for purposes of clarity the description will bedirected to the three chamber unit as shown.

Each of the chambers 11, 12'and 13 are in communication with both theincoming or low-pressure slurry pipeline l4 and the outgoing orhigh-pressure slurry pipeline 15. Lines 16, 17 and 18 connect thechambers 11, 12, and 13, respectively, to the incoming slurry pipeline14 and lines 19, 20 and 21 connect the chambers 11, 12 and 13,respectively, to the outgoing slurry pipeline 15. Check valves 22, 23and 24 on the lines 16, 17, 18, respectively, are adapted to permitslurry to flow from the incoming slurry pipeline 14 into the chambers,as shown by the directional arrows 25, and check valves 26, 27 and 28,on the lines 19,20 and 21, respectively, are adapted to permit slurry toflow from the chambers into the outgoing slurry pipeline 15, as shown bythe directional arrows 29. The check valves operate according to thepressure differential in the respective lines.

The slurry is pressurized in each chamber by a liquid which isseparately pressurized by a pump 30, preferably a centrifugal pump ofthe type used in petroleum pipelining systems. The pump is run by amotor 31. While only a single pump and motor are shown in FIG. 1, it isclear that a plurality of pumps and/or motors can be employed. Thepressurized liquid is recirculated through a conduit 32. Lines 33 and 34connect the pump 30 to the low liquid pressure and the high liquidpressure sides, 35 and 36, respectively, of the conduit 32. Valves 37and 38 on the lines 33 and 34, respectively, are simply pump isolationvalves.

Each of the chambers ll, 12 and 13 are in communication with both thelow-pressure side 35 of the conduit 32 and the high-pressure side 36 ofthe conduit 32. Lines 39, 40 and 4] connect the chambers ll, 12 and 13,respectively, to the highpressure side 36 and lines 42, 43 and 44connect the chambers 11, 12 and 13, respectively, to the low-pressureside 35. Valves lD, 2-D and 3-D on the lines 39, 40 and 41,respectively, are adapted to permit the pressurized liquid to flow fromthe conduit 32 into the chambers, as shown by the directional arrows 45,and valves 1-S, 2-S and 3-S on the lines 42, 43 and 44, respectively,are adapted to permit the liquid to flow from the chambers back into theconduit 32, as shown by the directional arrows 46. These valves aresequentially operated by a timing system which is dependent on themovement of the slurry in the chambers and the sequencing of the valveoperation is such that the slurry is both removed from the incomingslurry pipeline and reintroduced into the outgoing slurry pipeline in apulsation-free manner which substantially prevents a variation in thevelocity of the slurry flow through the pipeline. The timing system andthe sequencing will be described more fully below.

Directing attention now to the individual chambers, the chambers in thepumping unit, as stated before, are all identical and each chamberincludes a mechanical separator 47 which separates the slurry from thehydraulic liquid or medium in the chamber and prevents attenuation atthe interface of the slurry and liquid and contamination of the liquidwith slurry. The separator 47 moves in accordance with the movement ofthe slurry in the chamber as indicated by the directional ar rows 470.In the preferred embodiment shown in FIG. 1 the separator 47 movesslidably along the walls of the chamber and is in the form of a pistonor other similar means such as an inflatable sealing ball. Means areprovided to prevent leakage between the piston and the walls of thechamber. Preferably a pair of detector switches 48 and 49 are providedwith each chamber, however, as will be seen later the pumping unit canoperate when only one detector switch is provided with each chamber.Detector switch 48 is activated when the chamber is nearly full ofslurry and the separator has been moved to an actuating position by theslurry filling the chamber. Detector switch 49 is actuated when thechamber is nearly empty of slurry and the separator has been moved to anactuating position by the slurry emptying from the chamber. Theseparator 47 can actuate the detector switches 48 and 49 in variousmanners such as mechanical contacts or magnetic control. The detectorswitches in turn either directly initiate the operation of the valves orthey can initiate the operation of a sequence timer (not shown) which inturn would control the valve operation.

In the alternative embodiment of the chamber, shown in FIG. 3 anddesignated generally 100, the separator 101 includes a cylindrical cupmember 102 which is connected to the walls of the chamber 100 by aflexible member 103. Detector switches 104 and 105 are again actuatedwhen the chamber is nearly full or empty of slurry, respectively, andactuated by the cup member 102 when it is moved into an actuatingposition by the movement of the slurry in the chamber.

In the other embodiment shown in FIG. 4 the chamber, generallydesignated 200, includes a flexible diaphragm member 201 which isconnected to the inner walls of the chamber. Detector switches 202 and203 are actuated when the chamber is nearly full or empty of slurry,respectively. A contact member 204, connected to the diaphragm 201 asshown diagrammatically in FIG. 3, extends beyond the chamber 200 and theswitches 202 and 203 are actuated by the contact member 204 when it ismoved to an actuating position by the diaphragm which is in turn movedby the movement of the slurry in the chamber. FIG. 4 also points out afurther invention in the invention, that is, additional chambers may beplaced in parallel operation with the other chamber 200, as shown by thephantom lines 205. This, of course, means that the same number ofchambers will be placed in parallel with the other two chambers.

While not shown in the drawings, another variation of this inventionwould be to place the chambers in a more or less vertical position andto use a recirculating pressurized liquid with either a heavier orlighter specific gravity than the specific gravity of the slurry. Inthis instance, the mechanical separator 47 is not necessary as thedifference in specific gravity between the slurry and the recirculatingliquid would maintain a stable interface in the chambers. Therecirculating liquid or slurry having the highest specific gravity woulddetermine which end of the chamber the slurry or the liquid would beintroduced, the heaviest one always being introduced at the bottom end.It should be noted that when the mechanical separator is not used othermeans of sensing and switching will need to be employed.

Before discussing the timing system and the sequence ofthe valves duringoperation of the pumping unit, certain other features of the unit shouldbe noted. In order to provide for the dissipation of heat of thehydraulic medium or liquid generated by the inefficiency of thecentrifugal pump or pumps 30, the pumping unit 10 includes a heatexchanger 50 which cools the hydraulic liquid by utilizing thetemperature differential between the hydraulic liquid and the outgoingslurry. A solids separator 51 is also included on the recirculatingconduit 35 to further prevent the inclusion of solids in the hydraulicliquid which might damage the centrifugal pump or pumps 30,

A further feature relates to the balance of slurry and liquid in thechambers. When three chambers are used, at any given instant, undernormal operations, the total volume of hydraulic liquid in all threechambers will be approximately one-third the total volume of slurry inall three chambers. However, because of liquid or slurry slippage pastthe mechanical separator 47 or because of pump seal leakage, thisbalance can gradually go one way or the other. If allowed to be carriedto the extreme, all the chambers at the same time would either becomefull of slurry or become full of hydraulic liquid which would result ina stoppage of the pump unit 10. To maintain this unbalancing of liquidvolume versus slurry volume within certain predetermined tolerances,means 52 are provided for both the injection of liquid into and for thedrainage of liquid from the recirculating system, depending on which waythe unbalance has occurred. The unbalance is sensed by instrumentation(not shown) detecting predetermined extreme limits of travel of themechanical separators. If the chambers are short on water, allmechanical separators 47 will fall short of reaching the slurry end ofthe chambers. If the chambers have too much water, all the mechanicalseparators 47 will fall short of reaching the liquid end of thechambers. The sensing instrumentation will detect these travel limitsand depending on which end of the chambers the separator travel fallsshort, such instrumentation will determine whether liquid should beinjected or drained from the recirculating system. Each injection ordrainage will be controlled to a predetermined amount of volume. Sensingthe location of the mechanical separators need only take place on onechamber, as the length and position ofstrokes will be identical in allthe chambers.

FIG. 2 diagrammatically represents the sequence of the valve operationduring operation of the pump unit 10. The darkened portion in thedrawing represents an open valve. During a complete cycle in which allthe chambers in a three chamber unit have first filled with low-pressureslurry and then emptied of high-pressure slurry, the sequence is asfollows:

Beginning at a time in the cycle shown approximately in FIG. I, slurryis emptying from chamber 11 and slurry is filling into chamber 13, thiscontinues until the separator 47 in chamber 11 moves down with theslurry to a position to actuate switch 49 on chamber 11. The switch 49on chamber 11 then opens valve 2-D which starts the emptying of slurryfrom chamber 12 and which when open begins the closing of valve l-D.Valve l-D when closed begins the opening of valve 1-5 which starts thefilling of slurry into chamber 11 and l-S when open begins the closingof 3-S.

The valves then remain in this position until the separator 47 inchamber 12 moves down with the slurry to a position to actuate switch 49on chamber 12. The switch 49 on chamber 12 then opens valve 3D. whichstarts the emptying of slurry from chamber 13 and which when open beginsthe closing of valve 2-D. Valve 2-D when closed begins the opening ofvalve 2-S which starts the filling of slurry into chamber 12 and 2-Swhen open begins the closing of 1-5.

The valves then remain in this position until the separator 47 inchamber 13 moves down with the slurry to a position to actuate switch 49on chamber 13 then opens valve 1-D which starts the emptying of chamber11 and which when open begins the closing of valve 3-D. Valve 3-D whenclosed begins the opening of valve 3-S which starts the filling ofslurry into chamber 13 and 3-5 when open begins the closing of 2-S. Thevalves then remain in this position until the separator 47 in chamber 11actuates switch 49 on chamber 11 and the cycle is repeated.

For the sake of clarity of description, only detector switches 49 on thechambers ll, 12 and 13 have been included in the description of thevalve sequence. However, in actual operation the detector switches 48 onchambers 11, 12 and 13 play an important roll. For instance, when theamount of slurry in all three chambers is greater than two-thirds thetotal volume of all the chambers the mechanical separator 47 in chamber13 would reach the position to actuate the switch 48 on chamber 13before the separator 47 in chamber 11 reached the position to actuatethe switch 49 on chamber 11. If this occurred, the switch 48 on chamber13 would open valve 2-D to start the sequence described above.Similarly, switch 48 on chamber 11 will open valve 3-D and start thatsequence and switch 48 on chamber 12 will open valve 1-D to begin thatsequence. On the other hand, if the total volume of the slurry is lessthan two-thirds the total volume of the chambers, then switches 49 willstart the valve sequence. Detector switches on either end of theseparator stroke in this manner will thus prevent the pump unit fromgetting into a locked position. These additional detector switches 48also provide for slippage of the mechanical separator 47 in the slurryor recirculating liquid and no matter how severe the slippage, thesequence of operation cannot get out of sequence, that is, the dischargeof slurry from chamber 12 always follows the discharge of slurry fromchamber 11, and the discharge of slurry from chamber 13 always followsthe discharge of slurry from chamber 12, and the discharge of slurryfrom chamber 11 always follows the discharge of slurry from chamber 13.

The pump unit with three or more chambers sequenced in this mannerprovides for the pressurizing of the slurry in a pulsation-free mannerbecause there is a continuous flow of slurry at all times into and outof the pipeline which is uneffected by the valve switching. The pumpunit is such that a centrifugal pump or pumps can be employed to raisethe pressure head of the slurry without the pumps being subjected to theabrasiveness of the slurry.

Iclaim:

1. A pump unit to increase the pressure of slurry being transportedthrough a pipeline, comprising: at least three chambers; pressurizingmeans adapted to alternately apply high and low pressure to each saidchamber; means to provide for the flow of slurry from the pipeline intoone end of each said chamber during the application of low pressure tofill each said chamber with slurry and to provide for the flow of slurryfrom said one end of each said chamber into the pipeline during theapplication of high pressure to empty each said chamber of slurry; andcontrol means associated with the emptying and filling of slurry in eachsaid chamber to cause the low pressure to be applied at all times to atleast one of said chambers and the high pressure to be applied at alltimes to at least another one of said chambers and to cause the high andlow pressure to be applied sequentially to said chambers with theapplication of either pressure to each chamber beginning before the endof the application of a corresponding like pressure to the precedingchamber in the sequence whereby at all times there is a continuous flowof slurry from the pipeline into at least one of said chambers and acontinuous flow of slurry from at least another one of said chambersinto the pipeline to provide the increased pressure to the slurry flowin the pipeline while avoiding undesirable pulsations.

2. The pump unit of claim 1, wherein said control means includes valvemeans associated with said other end of each said chamber which regulatethe alternate application of the high and low pressure to each saidchamber, switch means associated with each said chamber whichsequentially operate said valve means, and actuating means in each saidchamber associated with slurry flow therein operably contacting saidswitch means at predetermined intervals depending on the relativeamounts ofslurry in said chambers.

3. The pump unit of claim 2, wherein said actuating means comprises aseparator in each said chamber, each said separator in contact with theslurry in each said chamber and moveable in each said chamber relativeto the amount of slurry in each said chamber.

4. The pump unit of claim 2, wherein each said chamber comprises asufficiently large volume which requires a substantial filling andemptying period thereby delaying the actuation of said switch means andreducing the operation time of s aid value means.

,5. The pump unit of claim 4, wherein said chamber is cylindrical andthe length of each said chamber exceeds 25 feet.

.6. A pump unit to increase the pressure of slurry being transportedthrough a pipeline, comprising: first, second and third chambers;pressurizing means adapted to alternately apply high and low pressure toeach said chamber; means to provide for the flow of slurry from thepipeline into one end of each said chamber during the application of lowpressure to fill each said chamber with slurry and to provide for theflow of slurry from said one end of each said chamber into the pipelineduring the application of high pressure to empty each said chamber ofslurry; control means associated with the emptying and filling of slurryin each said chamber to cause the high and low pressure to be appliedsequentially to said chambers, said control means including valve meansassociated with each said chamber for regulating the alternateapplication of the high and low pressure to each said chamber, switchmeans associated with each said chamber which operate said valve means,and actuating means in each said chamber associated with slurry flowtherein operably contacting said switch means at predetermined intervalsto cause said valve means to operate according to a sequence wherebywhen slurry is flowing from said first chamber and into said thirdchamber and when said third chamber is near full, slurry begins to flowsimultaneously from said second chamber, slurry flow from said firstchamber is then stopped and slurry begins to flow into said firstchamber simultaneously with slurry flow into said third chamber, slurryflow into said third chamber is then stopped, and when said firstchamber is near full, slurry begins to flow simultaneously from saidthird chamber, slurry flow from said second chamber is then stopped andslurry begins to flow into said second chamber simultaneously withslurry flow into said first chamber, slurry flow into said first chamberis then stopped, and when said second chamber is near full, slurrybegins to flow simultaneously from said first chamber, slurry flow fromsaid third chamber is then stopped and slurry begins to flow into saidthird chamber simultaneously with slurry flow into second chamber,slurry flow into said second chamber is then stopped and the sequencebegins again and is repeated.

7. The pump unit of claim 6, wherein second switch means associated witheach said chamber are provided, said first switch means positioned toactuate and maintain said valve sequence when said chambers contain afirst predetermined amount of slurry and said second switch meanspositioned to actuate and maintain said valve sequence when saidchambers contain a second predetermined amount of slurry.

8. The pump unit of claim 7, wherein said first predetermined amount isequal to and greater than two-thirds the total volume of said chambersand said second predetermined amount is equal to and less thantwo-thirds the total volume of said chambers.

9. A pumping apparatus comprising: a plurality of at least threechambers; a pipeline transporting a first fluid, said pipeline incommunication with one end of each said chamber to provide for flowofsaid first fluid from said pipeline through said one end into eachsaid chamber and to provide for flow of said first fluid from each saidchamber through said one end back into said pipeline; a conduit carryinga second fluid in a closed circuit; a pump assembly, in said closedcircuit connected to said conduit and adapted to pressurize said secondfluid; said conduit in communication with said other end of each saidchamber to provide for flow of said second fl'uid when pressurized fromsaid conduit into each said chamber through said other end and toprovide for flow of said second fluid from each said chamber, saidsecond fluid creating a high-pressure zone in said chambers when flowinginto said chambers to cause said first fluid to flow from said chambersand creating a low-pressure zone in said chambers when flowing from saidchambers to cause said first fluid to flow into said chambers; separatormeans in each said chamber to prevent communication of said first fluidwith said pump assembly and to maintain said second fl'uid in saidclosed circuit; valve means in association with said other end toalternate flow of said second fluid into and from each said chamber; andcontrol means to operate said valve means in a sequence which providesat all times a continuous flow of said first fluid into and acorresponding flow of said second fluid from at least one of saidchambers and a continuous flow of said first fluid from and acorresponding continuous flow of said second fluid into at least anotherone of said chambers to provide a nonpulsating flow of said first fluidin said pipeline.

10. The pumping apparatus of claim 9, wherein said pump assemblyincludes at least one centrifugal pump.

11. The pumping apparatus of claim 9, wherein said second fluid isrecirculated in said conduit from said pump assembly into said chambersand then from said chambers back to said pump assembly.

12. The pumping apparatus of claim 11, wherein a heat exchanger isprovided in said closed circuit which utilizes the temperaturedifference between the second fluid flowing in said conduit from saidchambers back to said pump assembly and the first fluid in said pipelineflowing from said chambers to cool said second fluid before said secondfluid is recirculated back to said pump assembly.

13. The pumping apparatus of claim 11, wherein said conduit includes asolids separator in said closed circuit to remove solids from saidsecond liquid before it passes to said pump assembly.

14. The pumping apparatus of claim 9, wherein said separator meansincludes a separator in each said chamber positioned between theinterface of said first fluid and said second fluid in each said chamberand moveable relative to the movement of said first and second fluids ineach said chamber.

15. The pumping apparatus of claim 14, wherein said separator comprisesa moveable member slidably mounted to the walls of each said chamber andmeans to prevent leakage between said moveable member and the walls ofeach said chamber.

16. The pumping apparatus of claim 14, wherein said separator comprisesa flexible diaphragm member sealably secured to the walls of each saidchamber.

17. The pumping apparatus of claim 9, wherein said control meansincludes switch means in association with each said chamber, said switchmeans being actuated when each said chamber contains a predeterminedamount of first fluid.

18. The pumping apparatus of claim 17, wherein said switch means isactuated by said separator means.

19. The pumping apparatus of claim 9, wherein said first fluid comprisesa mixture ofliquid and solid particles.

20. A pumping apparatus of claim 9, wherein first, second and thirdchambers are employed.

21. The pumping apparatus of claim 20, wherein said valve means includesfirst, second and third inlet and outlet valves, said first, second andthird inlet valves regulate the flow of said second fluid into saidfirst, second and third chambers, respectively, and said first, secondand third outlet valves regulate the flow of said second fluid from saidfirst, second and third chambers, respectively; and said control meansincludes first, second and third switches associated with said first,second and third chambers, respectively, whereby, while said first fluidis flowing from said first chamber and said second fluid is flowing fromsaid third chamber and said second chamber is full of said first fluid,said first switch is actuated and operates and begins the opening ofsaid second inlet valve to begin the flow of said second fluid into saidsecond chamber, said second inlet valve when open then begins theclosing of said first inlet valve, said first inlet valve when closedthen begins the opening of said first outlet valve to begin the flow ofsaid first fluid into said first chamber, said first outlet valve whenopen then begins the closing of said third outlet valve, subsequentlysaid second switch is actuated and operates and begins the opening ofsaid third inlet valve to begin the flow of said second fluid into saidthird chamber, said third inlet valve when open then begins the closingof said second inlet valve, said second inlet valve when closed thenbegins the opening of said second outlet valve to begin the flow of saidfirst fluid into said second chamber, said second outlet valve when openthen begins the closing of said first outlet valve, subsequently saidthird switch is actuated and operates and begins the opening of saidfirst inlet valve to begin the flow of said second fluid into said firstchamber, said first inlet valve when open then begins the closing ofsaidthird inlet valve, said third inlet valve when closed then begins theopening of said third outlet valve to begin the flow ofsaid first fluidinto said third chamber, said third outlet valve when open then beginsthe closing of said second outlet valve, subsequently said first switchis actuated and the cycle is repeated.

22. A pumping method to increase the pressure of a first fluid flowingthrough a pipeline, the steps comprising:

applying for a period of time low pressure to each chamber of a group ofat least three chambers to cause said first fluid to pass into saidchambers from the pipeline and alternately applying for a substantiallyequal period of time high pressure to cause said first fluid to passfrom said chambers and back into the pipeline;

passing at a controlled rate a volume of said first fluid from thepipeline into at least one of said chambers while applying low pressure;

simultaneously passing at an equal rate an equal volume of said firstfluid from at least another one of said chambers while applying highpressure; and sequentially applying said high and low pressure to saidgroup of chambers to provide at all times a continuous flow of saidfirst fluid from said pipeline into said group of chambers and acontinuous flow of said first fluid from said group of chambers backinto said pipeline to provide the increased pressure to said first fluidwithout creating pulsations in the flow of the first fluid through thepipeline. 23. The method of claim 22, wherein a second fluid whenpressurized is passed alternately into said chambers to apply highpressure to said chambers and is withdrawn alternately from saidchambers to apply low pressure to said chambers.

24. The method of claim 23, wherein at least one centrifugal pump isemployed to pressurize said second fluid.

25. The method of claim 24, wherein each said chamber is provided with aseparator to separate said second fluid from said first fluid in saidchambers to prevent communication of said first fluid with saidcentrifugal pump.

26. The method of claim 23, wherein valve means are provided to controlthe flow of said second fluid into and from said chambers.

27. The method of claim 26, wherein said valve means are sequentiallyoperated by switch means which are associated with predetermined amountsof said first fluid in each said chamber.

28. A pumping method to increase the pressure of a slurry flowingthrough a pipeline, the steps comprising:

providing a group of at least three pressure chambers, each of which isin communication with the pipeline;

alternately applying first a low pressure and then a high pressure toeach chamber to cause the slurry to first flow from the pipeline into achamber and then flow from the chamber back into the pipeline;

applying to each chamber the low pressure until the chamber is filledwith slurry and applying to each filled chamber the alternate highpressure until the chamber is empty of the slurry;

applying low pressure at all times to at least one of the chambers toprovide a continuous flow of slurry into the group of chambers andsimultaneously applying high pressure to at least another one of thechambers to pro vide a continuous flow of slurry from the group ofchambers back to the pipeline; and

applying the low pressure to the chambers in sequence to begin thefilling of another chamber before the preceding chamber in the sequenceis filled and applying the high pressure to the chambers in a similarsequence to begin the discharge of another chamber before the precedingchamber in the sequence is empty whereby pulsations in the incoming andoutgoing slurry are avoided.

29. The method of claim 28, wherein a fluid in a closed circuit iscommunicated to each chamber to provide for the application of highpressure and communicated from each chamber to provide for theapplication of low pressure.

30. The method of claim 29, wherein centrifugal pump means in the closedcircuit pressurize the fluid in the circuit.

1. A pump unit to increase the pressure of slurry being transportedthrough a pipeline, comprising: at least three chambers; pressurizingmeans adapted to alternately apply high and low pressure to each saidchamber; means to provide for the flow of slurry from the pipeline intoone end of each said chamber during the application of low pressure tofill each said chamber with slurry and to provide for the flow of slurryfrom said one end of each said chamber into the pipeline during theapplication of high pressure to empty each said chamber of slurry; andcontrol means associated with the emptying and filling of slurry in eachsaid chamber to causE the low pressure to be applied at all times to atleast one of said chambers and the high pressure to be applied at alltimes to at least another one of said chambers and to cause the high andlow pressure to be applied sequentially to said chambers with theapplication of either pressure to each chamber beginning before the endof the application of a corresponding like pressure to the precedingchamber in the sequence whereby at all times there is a continuous flowof slurry from the pipeline into at least one of said chambers and acontinuous flow of slurry from at least another one of said chambersinto the pipeline to provide the increased pressure to the slurry flowin the pipeline while avoiding undesirable pulsations.
 2. The pump unitof claim 1, wherein said control means includes valve means associatedwith said other end of each said chamber which regulate the alternateapplication of the high and low pressure to each said chamber, switchmeans associated with each said chamber which sequentially operate saidvalve means, and actuating means in each said chamber associated withslurry flow therein operably contacting said switch means atpredetermined intervals depending on the relative amounts of slurry insaid chambers.
 3. The pump unit of claim 2, wherein said actuating meanscomprises a separator in each said chamber, each said separator incontact with the slurry in each said chamber and moveable in each saidchamber relative to the amount of slurry in each said chamber.
 4. Thepump unit of claim 2, wherein each said chamber comprises a sufficientlylarge volume which requires a substantial filling and emptying periodthereby delaying the actuation of said switch means and reducing theoperation time of said value means.
 5. The pump unit of claim 4, whereinsaid chamber is cylindrical and the length of each said chamber exceeds25 feet.
 6. A pump unit to increase the pressure of slurry beingtransported through a pipeline, comprising: first, second and thirdchambers; pressurizing means adapted to alternately apply high and lowpressure to each said chamber; means to provide for the flow of slurryfrom the pipeline into one end of each said chamber during theapplication of low pressure to fill each said chamber with slurry and toprovide for the flow of slurry from said one end of each said chamberinto the pipeline during the application of high pressure to empty eachsaid chamber of slurry; control means associated with the emptying andfilling of slurry in each said chamber to cause the high and lowpressure to be applied sequentially to said chambers, said control meansincluding valve means associated with each said chamber for regulatingthe alternate application of the high and low pressure to each saidchamber, switch means associated with each said chamber which operatesaid valve means, and actuating means in each said chamber associatedwith slurry flow therein operably contacting said switch means atpredetermined intervals to cause said valve means to operate accordingto a sequence whereby when slurry is flowing from said first chamber andinto said third chamber and when said third chamber is near full, slurrybegins to flow simultaneously from said second chamber, slurry flow fromsaid first chamber is then stopped and slurry begins to flow into saidfirst chamber simultaneously with slurry flow into said third chamber,slurry flow into said third chamber is then stopped, and when said firstchamber is near full, slurry begins to flow simultaneously from saidthird chamber, slurry flow from said second chamber is then stopped andslurry begins to flow into said second chamber simultaneously withslurry flow into said first chamber, slurry flow into said first chamberis then stopped, and when said second chamber is near full, slurrybegins to flow simultaneously from said first chamber, slurry flow fromsaid third chamber is then stopped and slurry begins to flow into saidthird chamber simultaneously with slurry flow iNto second chamber,slurry flow into said second chamber is then stopped and the sequencebegins again and is repeated.
 7. The pump unit of claim 6, whereinsecond switch means associated with each said chamber are provided, saidfirst switch means positioned to actuate and maintain said valvesequence when said chambers contain a first predetermined amount ofslurry and said second switch means positioned to actuate and maintainsaid valve sequence when said chambers contain a second predeterminedamount of slurry.
 8. The pump unit of claim 7, wherein said firstpredetermined amount is equal to and greater than two-thirds the totalvolume of said chambers and said second predetermined amount is equal toand less than two-thirds the total volume of said chambers.
 9. A pumpingapparatus comprising: a plurality of at least three chambers; a pipelinetransporting a first fluid, said pipeline in communication with one endof each said chamber to provide for flow of said first fluid from saidpipeline through said one end into each said chamber and to provide forflow of said first fluid from each said chamber through said one endback into said pipeline; a conduit carrying a second fluid in a closedcircuit; a pump assembly, in said closed circuit connected to saidconduit and adapted to pressurize said second fluid; said conduit incommunication with said other end of each said chamber to provide forflow of said second fluid when pressurized from said conduit into eachsaid chamber through said other end and to provide for flow of saidsecond fluid from each said chamber, said second fluid creating ahigh-pressure zone in said chambers when flowing into said chambers tocause said first fluid to flow from said chambers and creating alow-pressure zone in said chambers when flowing from said chambers tocause said first fluid to flow into said chambers; separator means ineach said chamber to prevent communication of said first fluid with saidpump assembly and to maintain said second fluid in said closed circuit;valve means in association with said other end to alternate flow of saidsecond fluid into and from each said chamber; and control means tooperate said valve means in a sequence which provides at all times acontinuous flow of said first fluid into and a corresponding flow ofsaid second fluid from at least one of said chambers and a continuousflow of said first fluid from and a corresponding continuous flow ofsaid second fluid into at least another one of said chambers to providea nonpulsating flow of said first fluid in said pipeline.
 10. Thepumping apparatus of claim 9, wherein said pump assembly includes atleast one centrifugal pump.
 11. The pumping apparatus of claim 9,wherein said second fluid is recirculated in said conduit from said pumpassembly into said chambers and then from said chambers back to saidpump assembly.
 12. The pumping apparatus of claim 11, wherein a heatexchanger is provided in said closed circuit which utilizes thetemperature difference between the second fluid flowing in said conduitfrom said chambers back to said pump assembly and the first fluid insaid pipeline flowing from said chambers to cool said second fluidbefore said second fluid is recirculated back to said pump assembly. 13.The pumping apparatus of claim 11, wherein said conduit includes asolids separator in said closed circuit to remove solids from saidsecond liquid before it passes to said pump assembly.
 14. The pumpingapparatus of claim 9, wherein said separator means includes a separatorin each said chamber positioned between the interface of said firstfluid and said second fluid in each said chamber and moveable relativeto the movement of said first and second fluids in each said chamber.15. The pumping apparatus of claim 14, wherein said separator comprisesa moveable member slidably mounted to the walls of each said chamber andmeans to prevent leakage between said moveable member and the walls ofeach said chamber.
 16. ThE pumping apparatus of claim 14, wherein saidseparator comprises a flexible diaphragm member sealably secured to thewalls of each said chamber.
 17. The pumping apparatus of claim 9,wherein said control means includes switch means in association witheach said chamber, said switch means being actuated when each saidchamber contains a predetermined amount of first fluid.
 18. The pumpingapparatus of claim 17, wherein said switch means is actuated by saidseparator means.
 19. The pumping apparatus of claim 9, wherein saidfirst fluid comprises a mixture of liquid and solid particles.
 20. Apumping apparatus of claim 9, wherein first, second and third chambersare employed.
 21. The pumping apparatus of claim 20, wherein said valvemeans includes first, second and third inlet and outlet valves, saidfirst, second and third inlet valves regulate the flow of said secondfluid into said first, second and third chambers, respectively, and saidfirst, second and third outlet valves regulate the flow of said secondfluid from said first, second and third chambers, respectively; and saidcontrol means includes first, second and third switches associated withsaid first, second and third chambers, respectively, whereby, while saidfirst fluid is flowing from said first chamber and said second fluid isflowing from said third chamber and said second chamber is full of saidfirst fluid, said first switch is actuated and operates and begins theopening of said second inlet valve to begin the flow of said secondfluid into said second chamber, said second inlet valve when open thenbegins the closing of said first inlet valve, said first inlet valvewhen closed then begins the opening of said first outlet valve to beginthe flow of said first fluid into said first chamber, said first outletvalve when open then begins the closing of said third outlet valve,subsequently said second switch is actuated and operates and begins theopening of said third inlet valve to begin the flow of said second fluidinto said third chamber, said third inlet valve when open then beginsthe closing of said second inlet valve, said second inlet valve whenclosed then begins the opening of said second outlet valve to begin theflow of said first fluid into said second chamber, said second outletvalve when open then begins the closing of said first outlet valve,subsequently said third switch is actuated and operates and begins theopening of said first inlet valve to begin the flow of said second fluidinto said first chamber, said first inlet valve when open then beginsthe closing of said third inlet valve, said third inlet valve whenclosed then begins the opening of said third outlet valve to begin theflow of said first fluid into said third chamber, said third outletvalve when open then begins the closing of said second outlet valve,subsequently said first switch is actuated and the cycle is repeated.22. A pumping method to increase the pressure of a first fluid flowingthrough a pipeline, the steps comprising: applying for a period of timelow pressure to each chamber of a group of at least three chambers tocause said first fluid to pass into said chambers from the pipeline andalternately applying for a substantially equal period of time highpressure to cause said first fluid to pass from said chambers and backinto the pipeline; passing at a controlled rate a volume of said firstfluid from the pipeline into at least one of said chambers whileapplying low pressure; simultaneously passing at an equal rate an equalvolume of said first fluid from at least another one of said chamberswhile applying high pressure; and sequentially applying said high andlow pressure to said group of chambers to provide at all times acontinuous flow of said first fluid from said pipeline into said groupof chambers and a continuous flow of said first fluid from said group ofchambers back into said pipeline to provide the increased pressure tosaid first fluid without creating pulsations in the flow of the firstfluid through the pipeline.
 23. The method of claim 22, wherein a secondfluid when pressurized is passed alternately into said chambers to applyhigh pressure to said chambers and is withdrawn alternately from saidchambers to apply low pressure to said chambers.
 24. The method of claim23, wherein at least one centrifugal pump is employed to pressurize saidsecond fluid.
 25. The method of claim 24, wherein each said chamber isprovided with a separator to separate said second fluid from said firstfluid in said chambers to prevent communication of said first fluid withsaid centrifugal pump.
 26. The method of claim 23, wherein valve meansare provided to control the flow of said second fluid into and from saidchambers.
 27. The method of claim 26, wherein said valve means aresequentially operated by switch means which are associated withpredetermined amounts of said first fluid in each said chamber.
 28. Apumping method to increase the pressure of a slurry flowing through apipeline, the steps comprising: providing a group of at least threepressure chambers, each of which is in communication with the pipeline;alternately applying first a low pressure and then a high pressure toeach chamber to cause the slurry to first flow from the pipeline into achamber and then flow from the chamber back into the pipeline; applyingto each chamber the low pressure until the chamber is filled with slurryand applying to each filled chamber the alternate high pressure untilthe chamber is empty of the slurry; applying low pressure at all timesto at least one of the chambers to provide a continuous flow of slurryinto the group of chambers and simultaneously applying high pressure toat least another one of the chambers to provide a continuous flow ofslurry from the group of chambers back to the pipeline; and applying thelow pressure to the chambers in sequence to begin the filling of anotherchamber before the preceding chamber in the sequence is filled andapplying the high pressure to the chambers in a similar sequence tobegin the discharge of another chamber before the preceding chamber inthe sequence is empty whereby pulsations in the incoming and outgoingslurry are avoided.
 29. The method of claim 28, wherein a fluid in aclosed circuit is communicated to each chamber to provide for theapplication of high pressure and communicated from each chamber toprovide for the application of low pressure.
 30. The method of claim 29,wherein centrifugal pump means in the closed circuit pressurize thefluid in the circuit.